Investigation of the free radical scavenging ability of l-tryptophan and its derivatives using experimental methods and quantum chemical calculations.

The free radical scavenging ability of l-tryptophan (LP) and 5-hydroxy-l-tryptophan (HLP) was evaluated using experimental and theoretical methods. The impact of antioxidant concentration on the scavenging of DPPH˙ and ABTS˙ free radicals was assessed for both compounds. The results indicated that HLP exhibited superior scavenging ability, with IC values of 31.

Triple-chain boron clusters: lengthening phosphorus doping and enhancing stability through {P} by {CH} substitution.

This theoretical study presents novel insights into the doping of boron clusters with an increasing number of dopant atoms, ranging from 1 to 4, that preserve the integrity of the original boron framework. The triple-chain forms of clusters B and B remain unchanged upon sequential addition of P atoms, showcasing a perfect isolobal substitution of {P} with {CH}. Similarities in the number of delocalized electrons are observed between pure and doped boron clusters, alongside the subsequent substitution of {P} with {CH}.

Evaluation of Free Radical Scavenging Ability of Triazole-3-Thiol: A Combination of Experimental and Theoretical Approaches.

An assessment of the free radical scavenging potential of 4-amino-5-phenyl-4H-1,2,4-triazole-3-thiol (AT) and 4-amino-5-(4-pyridyl)-4H-1,2,4-triazole-3-thiol (AP) involved a combination of experimental methodologies and theoretical calculations. In the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, AT exhibited an heightened efficacy in scavenging DPPH radicals compared to AP. This was evidenced by the notably lower IC value observed for AT (1.

Formation of pyramidal structures through mixing gold and platinum atoms: the AuPt clusters with + = 10.

The geometric and electronic structures of a small series of mixed gold and platinum AuPt clusters, with + = 10, were investigated using quantum chemical methods. A consistent tetrahedral pyramid structure emerges, displaying two patterns of structural growth by a notable critical point at = 5. This affects the clusters' electron population, chemical bonding, and stability.

The effect of MnCO on the gain coefficient for the I → I transition of Er ions and near-infrared emission bandwidth flatness of Er/Tm/Yb co-doped barium zinc silicate glasses.

The roles of Mn ions in the MnCO compound, leading to the formation of an Mn-Yb dimer and affecting the gain coefficient for the I → I transition of Er ions and near-infrared (NIR) emission bandwidth flatness of Er/Tm/Yb co-doped in SiO-ZnO-BaO (SZB) barium zinc silicate glasses, were investigated in this work. The composition of all elements from the original raw materials that exist in the host glasses was determined using energy-dispersive X-ray spectroscopy (EDS). Under the excitation of a 980 nm laser diode (LD), the NIR emission of Er/Tm/Yb-co-doped SZB glasses produced a bandwidth of about 430 nm covering the O, E, and C bands.

Revisiting conventional noncovalent interactions towards a complete understanding: from tetrel to pnicogen, chalcogen, and halogen bond.

Typical noncovalent interactions, including tetrel (TtB), pnicogen (PniB), chalcogen (ChalB), and halogen bonds (HalB), were systematically re-investigated by modeling the N⋯Z interactions (Z = Si, P, S, Cl) between NH - as a nucleophilic, and SiF, PF, SF and ClF - as electrophilic components, employing highly reliable methods. The characteristics of N⋯Z interactions when Z goes from Si to Cl, were examined through their changes in stability, vibrational spectroscopy, electron density, and natural orbital analyses. The binding energies of these complexes at CCSD(T)/CBS indicate that NH tends to hold tightly most with ClF (-34.

Upgrading nirmatrelvir to inhibit SARS-CoV-2 Mpro via DeepFrag and free energy calculations.

The first oral drug for the treatment of COVID-19, Paxlovid, has been authorized; however, nirmatrelvir, a major component of the drug, is reported to be associated with some side effects. Moreover, the appearance of many novel variants raises concerns about drug resistance, and designing new potent inhibitors to prevent viral replication is thus urgent. In this context, using a hybrid approach combining machine learning (ML) and free energy simulations, 6 compounds obtained by modifying nirmatrelvir were proposed to bind strongly to SARS-CoV-2 Mpro.

Optical band gaps and spectroscopy properties of Bi /Eu /Yb co-doped ( = 0, 2, 3; and = 2, 3) zinc calcium silicate glasses.

In this study, the indirect/direct optical band gaps and spectroscopy properties of Bi /Eu /Yb co-doped ( = 0, 2, 3; and = 2, 3) zinc calcium silicate glasses under different excitation wavelengths were investigated. Zinc calcium silicate glasses with the main compositions of SiO-ZnO-CaF-LaF-TiO were prepared by the conventional melting method. EDS analysis was performed to determine the elemental composition existing in the zinc calcium silicate glasses.